Two different sunflower lines with increased beta-tocopherol concentra tion in the seeds, LG-15 and T589, have been developed. The objective of the present research was to conduct a comparative genetic study of the increased beta-tocopherol concentration in both lines. Plants of LG-15 were reciprocally crossed with plants of T589 in 2003. The F1, F2, BC to LG-15 and BC to T589 seed generations were produced in the same environment in 2004 and analyzed for tocopherol profile. The results indicated a strong environmental effect on the increased levels of beta-tocopherol concentration in LG-15 and T589, which averaged 30.5% and 25.8%, respectively, in 2003 and 43.2% and 54.0%, respectively, in 2004. The comparison of individual plant means and standard errors of individual plant means for the F2 and BC generations with those in the non-segregating parental and F1 generations indicated no transgressive segregation for beta-tocopherol concentration in F2 or BC seeds. These results suggested that increased beta-tocopherol concentration in both lines is the result of genetic alterations at the same locus.